Polishing apparatuses for polishing the surface of a polishing target object (for example, a semiconductor wafer) comprise a polishing tool on which a polishing pad is mounted and polishing target object holding means such as a rotating support for holding the polishing target object and are configured to polish the surface of the polishing target object as a result of the polishing tool and polishing target object holding means being relatively moved with the polishing pad in a state of contact with the polishing target object held by polishing target object holding means. Polishing target object shavings generated throughout the surface polishing thereof and slurry dregs and so on of a slurry supplied to the surface to be polished of the polishing target object create blockages in the surface of the polishing pad of these polishing apparatuses which, as a result, must be dressed by a separately provided dresser (for example, see Japanese Unexamined Patent Application Publication Nos. H10-86056, 2003-68688 and 2004-25413).
The polishing pad provided on the polishing tool changes the polishing state of the polishing target object in accordance with its shape. In other words, the polishing state of a polishing target object can be adjusted by preparing a polishing pad of a predetermined shape. Accordingly, the polishing pad must be dressed not only to remove blockages of the pad surface but also to form the polishing pad in the aforementioned predetermined shape. The way that a polishing pad is planed changes when the relative position of the dresser with respect to the polishing pad is altered and, accordingly, the polishing pad shape can be gradually caused to approach the predetermined shape by dressing the polishing pad while measuring changes in the surface shape of the polishing pad.